Types of Bicycle Brake Levers

Modern road bikes use two different types of brake levers.  One style is integrated with the shift levers, where the whole shift/brake unit is one piece and meant to be mounted on traditional "drop" handlebars.  With this style, the rider pulls the lever toward the back of the bike to stop the bike, and pushes the levers to the side to shift.  Flat-bar road bikes use mountain components.  Mountain brake levers are a separate unit from the shifters.  This is because of the likelihood of crashes on a mountain bike, and the lower replacement cost of individual components!

On the mountain side, while there is not much visible difference between the brake lever types (V-brake, mechanical disc and hydraulic disc), they are very different inside, though.  V-brake levers and mechanical disc brake levers rely on cables that pull the brakes together during braking; hydraulic disc brakes rely on a closed system of hydraulic fluid to engage the brakes (like in cars).  There is a small reservoir of hydraulic fluid in the body of the brake lever housing.

Ask any 10 bike mechanics what their favorite brake systems are, and you'll hear 10 different answers.  Some brake systems are very intuitive and simple to work on - reliable and sturdy; others are more finicky.  Usually when a brake is adjusted properly (which with some systems is quite difficult), little maintenance is needed other than changing brake pads (and cables, if the system is mechanical).